1. Field
Aspects of the present invention relate to a laser beam irradiation apparatus for substrate sealing, and a method of manufacturing an organic light emitting display device by using the laser beam irradiation apparatus.
2. Description of the Related Art
Recently, display devices are being replaced with portable, thin flat panel display devices. Among the flat panel display devices, electroluminescent display devices are self-emissive display devices which have a wide viewing angle, an excellent contrast ratio, and a high response speed. Thus, flat panel displays are regarded as next-generation display devices.
An organic light emitting display device includes an emission layer formed of an organic material. The organic light emitting display devices have excellent luminosity, driving voltage, and response speed characteristics compared to inorganic light emitting display devices, and may realize multiple colors.
Conventional organic light emitting display devices have a structure in which at least one organic layer including an emission layer is interposed between two electrodes. When water or oxygen from the outside penetrates into the organic light emitting display device, an electrode material may be oxidized or exfoliation may occur. This may reduce the lifespan and light emitting efficiency of the organic light emitting device, and light emitting colors may be deteriorated. Accordingly, when manufacturing an organic light emitting display device, an organic light emitting device is usually sealed so as to isolate the organic light emitting device from the outside and so that water does not penetrate therein.
Examples of the sealing process include a method in which an inorganic thin film and an organic polymer (such as polyester (PET)) are laminated on a second electrode of an organic light emitting display device. Another sealing process includes a method in which an absorbent is formed in an encapsulation substrate, nitrogen gas is filled in the encapsulation substrate, and then a boundary of the encapsulation substrate is sealed using a sealant such as epoxy.
However, it is impossible to completely block such elements as water or oxygen penetrating from the outside, which destroy the organic light emitting device, by using the above methods. Thus, the methods cannot be applied to the organic light emitting display devices which are particularly vulnerable to water, and a process for realizing the methods is also complicated. In order to solve these problems, a method has been developed in which frit is used as a sealant to improve adhesive properties between a substrate of the organic light emitting device and an encapsulation substrate. By sealing an organic light emitting display device by coating frit on a glass substrate, the substrate of the organic light emitting device substrate and the encapsulation substrate are completely sealed, thereby effectively protecting the organic light emitting display device. A substrate is sealed using frit by coating the frit on a sealing unit of each of organic light emitting display devices and using a laser beam irradiation apparatus to irradiate a laser beam onto a sealing unit of each of the organic light emitting display devices, thereby hardening the frit and sealing the substrate.